scsi: be2iscsi: Fix boot flags in sysfs

The boot flags exported through sysfs was wrongly reverted to 2.  Use
boot flag 3 required per spec.

Bit 0 Block valid flag
Bit 1 Firmware booting selected

Signed-off-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>